Climate Change and Impact on Water Level of the Qinghai Lake Watershed

The meteorological and lake water level data from Gangcha and Tianjun meteorological stations around the Qinghai Lake during 1958-2009 were used to analyze the air temperature,precipitation,drought index and geotemperature characteristics of Qinghai Lake watershed and their impacts on the lake water level. The results are as follows: ( 1) The midterm of the 1980s witnessed the climate change from warm-dry to warm-wet and it became warmer and wetter since 2000. ( 2) The ascending tendency of geotemperature was more remarkable than that of air temperature with 0. 49-0. 64 ℃ rise per decade for 5-320 cm geotemperature and 0. 270. 31 ℃ per decade ( p 0.01) for air temperature. ( 3) Geotemperature had more apparent linear relationship with water level of Qinhai Lake than air temperature,which Pearson correlation coefficient was-0.66--0.8 ( p0.01) ,and it became more significant with the increase of soil depth. ( 4) The current drought conditions affected the water level variation of the second year,and the effect of precipitation and temperature on the water level of the next year is greater than that of the current year. ( 5) Pearson correlation and regression analysis indicated that the change of winter temperature had a negative correlation with water level of Qinhai Lake in the next year( p 0. 01) ,while the autumn precipitation had a significant positive correlation with water level in the next year ( p 0. 01) .